```css
/* ============================================================
   四虎影院 - zhiyitech.net
   完整样式表
   风格：深蓝科技 + 暖橙点缀，渐变Banner，毛玻璃，圆角卡片
   支持：响应式、暗色模式、滚动动画、hover动画
   ============================================================ */

/* ===== CSS 变量 ===== */
:root {
  /* 亮色模式 */
  --bg: #ffffff;
  --bg-soft: #f6f8fc;
  --bg-elevated: #ffffff;
  --text: #1e293b;
  --text-soft: #475569;
  --text-muted: #94a3b8;
  --brand: #1a2b4c;
  --brand-deep: #0f1e36;
  --brand-accent: #e85d3a;
  --brand-accent-hover: #d44a28;
  --brand-light: #eef2f9;
  --border: #dbe3f0;
  --border-hover: #c7d4ec;
  --radius-sm: 10px;
  --radius: 16px;
  --radius-lg: 24px;
  --radius-pill: 40px;
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.02);
  --shadow: 0 8px 30px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 20px 50px rgba(0, 0, 0, 0.1);
  --shadow-glow: 0 8px 30px rgba(232, 93, 58, 0.15);
  --glass-bg: rgba(255, 255, 255, 0.72);
  --glass-border: rgba(255, 255, 255, 0.6);
  --glass-blur: 18px;
  --gradient-hero: linear-gradient(135deg, #eef3fd 0%, #f8faff 40%, #ffffff 75%);
  --gradient-brand: linear-gradient(135deg, #1a2b4c 0%, #2d4a7c 100%);
  --gradient-accent: linear-gradient(135deg, #e85d3a 0%, #f0845f 100%);
  --gradient-card: linear-gradient(145deg, #ffffff 0%, #f8faff 100%);
  --font: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  --font-mono: "SF Mono", "Fira Code", "Consolas", monospace;
  --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 0.6s cubic-bezier(0.4, 0, 0.2, 1);
  --header-height: 72px;
}

/* ===== 暗色模式 ===== */
body.dark {
  --bg: #0b1220;
  --bg-soft: #111a2e;
  --bg-elevated: #16203a;
  --text: #e2e8f0;
  --text-soft: #a8b8d0;
  --text-muted: #6b7f9e;
  --brand: #dbeafe;
  --brand-deep: #93c5fd;
  --brand-accent: #f97316;
  --brand-accent-hover: #fb923c;
  --brand-light: #1a2438;
  --border: #253352;
  --border-hover: #3b4d72;
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.2);
  --shadow: 0 8px 30px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 20px 50px rgba(0, 0, 0, 0.55);
  --shadow-glow: 0 8px 30px rgba(249, 115, 22, 0.2);
  --glass-bg: rgba(17, 26, 46, 0.75);
  --glass-border: rgba(255, 255, 255, 0.08);
  --gradient-hero: linear-gradient(135deg, #111a2e 0%, #0b1220 60%, #0b1220 100%);
  --gradient-brand: linear-gradient(135deg, #1e3a5f 0%, #2d4a7c 100%);
  --gradient-accent: linear-gradient(135deg, #f97316 0%, #fb923c 100%);
  --gradient-card: linear-gradient(145deg, #16203a 0%, #111a2e 100%);
}

/* ===== 基础重置 ===== */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
}

body {
  font-family: var(--font);
  color: var(--text);
  background: var(--bg);
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  font-size: 16px;
  padding-top: var(--header-height);
  overflow-x: hidden;
  transition: background var(--transition), color var(--transition);
}

img,
svg {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: var(--brand);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--brand-accent);
}

ul {
  list-style: none;
}

button {
  font-family: inherit;
}

/* 自定义滚动条 */
::-webkit-scrollbar {
  width: 10px;
  height: 10px;
}

::-webkit-scrollbar-track {
  background: var(--bg-soft);
}

::-webkit-scrollbar-thumb {
  background: var(--border);
  border-radius: 10px;
  border: 2px solid var(--bg-soft);
}

::-webkit-scrollbar-thumb:hover {
  background: var(--text-muted);
}

/* 选中文字 */
::selection {
  background: var(--brand-accent);
  color: #fff;
}

/* ===== 布局容器 ===== */
.container {
  width: min(1180px, 92%);
  margin: 0 auto;
}

/* ===== 头部导航 ===== */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: var(--glass-bg);
  -webkit-backdrop-filter: blur(var(--glass-blur)) saturate(180%);
  backdrop-filter: blur(var(--glass-blur)) saturate(180%);
  border-bottom: 1px solid var(--border);
  height: var(--header-height);
  display: flex;
  align-items: center;
  transition: box-shadow var(--transition), background var(--transition),
    border-color var(--transition);
}

.nav-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
}

/* Logo */
.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  font-size: 1.35rem;
  color: var(--brand);
  letter-spacing: -0.02em;
  transition: transform var(--transition-fast);
}

.logo:hover {
  transform: scale(1.03);
  color: var(--brand);
}

.logo svg {
  width: 36px;
  height: 36px;
  border-radius: 10px;
  box-shadow: 0 4px 12px rgba(26, 43, 76, 0.25);
  transition: box-shadow var(--transition);
}

.logo:hover svg {
  box-shadow: 0 6px 18px rgba(26, 43, 76, 0.35);
}

/* 导航链接 */
.nav-links {
  display: flex;
  gap: 26px;
  font-size: 0.95rem;
  font-weight: 500;
}

.nav-links a {
  color: var(--text-soft);
  padding: 6px 0;
  border-bottom: 2px solid transparent;
  transition: color var(--transition-fast), border-color var(--transition-fast);
  position: relative;
}

.nav-links a::after {
  content: "";
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--gradient-accent);
  border-radius: 2px;
  transition: width var(--transition);
}

.nav-links a:hover {
  color: var(--brand);
}

.nav-links a:hover::after {
  width: 100%;
}

/* 导航操作区 */
.nav-actions {
  display: flex;
  align-items: center;
  gap: 14px;
}

/* 搜索框 */
.search-box {
  display: flex;
  align-items: center;
  background: var(--bg-soft);
  border-radius: var(--radius-pill);
  padding: 6px 14px;
  border: 1px solid var(--border);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast),
    background var(--transition-fast);
}

.search-box:focus-within {
  border-color: var(--brand-accent);
  box-shadow: 0 0 0 3px rgba(232, 93, 58, 0.12);
  background: var(--bg-elevated);
}

.search-box input {
  border: none;
  background: transparent;
  outline: none;
  font-size: 0.9rem;
  width: 140px;
  color: var(--text);
  font-family: inherit;
}

.search-box input::placeholder {
  color: var(--text-muted);
}

.search-box button {
  background: none;
  border: none;
  cursor: pointer;
  color: var(--text-soft);
  display: flex;
  padding: 4px;
  border-radius: 50%;
  transition: color var(--transition-fast), background var(--transition-fast);
}

.search-box button:hover {
  color: var(--brand-accent);
  background: var(--brand-light);
}

/* 主题切换 */
.theme-toggle {
  background: none;
  border: none;
  cursor: pointer;
  font-size: 1.2rem;
  padding: 8px;
  border-radius: 50%;
  transition: background var(--transition-fast), transform var(--transition-fast);
  line-height: 1;
}

.theme-toggle:hover {
  background: var(--bg-soft);
  transform: rotate(20deg) scale(1.1);
}

/* 菜单切换 */
.menu-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 1.6rem;
  cursor: pointer;
  color: var(--brand);
  padding: 4px 8px;
  border-radius: var(--radius-sm);
  transition: background var(--transition-fast);
}

.menu-toggle:hover {
  background: var(--bg-soft);
}

/* ===== 移动菜单 ===== */
.mobile-menu {
  display: none;
  position: fixed;
  top: var(--header-height);
  left: 0;
  right: 0;
  background: var(--glass-bg);
  -webkit-backdrop-filter: blur(var(--glass-blur)) saturate(180%);
  backdrop-filter: blur(var(--glass-blur)) saturate(180%);
  border-bottom: 1px solid var(--border);
  padding: 20px 0;
  z-index: 999;
  box-shadow: var(--shadow);
  animation: slideDown 0.3s ease;
}

@keyframes slideDown {
  from {
    opacity: 0;
    transform: translateY(-10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.mobile-menu.open {
  display: block;
}

.mobile-menu ul {
  display: flex;
  flex-direction: column;
  gap: 14px;
  padding: 0 5%;
}

.mobile-menu a {
  font-size: 1.05rem;
  font-weight: 500;
  color: var(--text-soft);
  padding: 8px 0;
  display: block;
  border-bottom: 1px solid transparent;
  transition: color var(--transition-fast), padding-left var(--transition-fast);
}

.mobile-menu a:hover {
  color: var(--brand);
  padding-left: 8px;
}

/* ===== 面包屑 ===== */
.breadcrumb {
  font-size: 0.85rem;
  color: var(--text-muted);
  padding: 16px 0;
  display: flex;
  gap: 8px;
  align-items: center;
  flex-wrap: wrap;
}

.breadcrumb a {
  color: var(--text-soft);
  transition: color var(--transition-fast);
}

.breadcrumb a:hover {
  color: var(--brand-accent);
}

.breadcrumb span {
  color: var(--text-muted);
}

/* ===== 首屏 Banner ===== */
.hero {
  padding: 60px 0 50px;
  background: var(--gradient-hero);
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: "";
  position: absolute;
  top: -120px;
  right: -120px;
  width: 420px;
  height: 420px;
  background: radial-gradient(circle, rgba(232, 93, 58, 0.12) 0%, transparent 70%);
  border-radius: 50%;
  pointer-events: none;
}

.hero::after {
  content: "";
  position: absolute;
  bottom: -160px;
  left: -100px;
  width: 380px;
  height: 380px;
  background: radial-gradient(circle, rgba(26, 43, 76, 0.08) 0%, transparent 70%);
  border-radius: 50%;
  pointer-events: none;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 50px;
  align-items: center;
  position: relative;
  z-index: 1;
}

.hero h1 {
  font-size: 2.8rem;
  font-weight: 800;
  line-height: 1.25;
  color: var(--brand);
  margin-bottom: 18px;
  letter-spacing: -0.02em;
}

.hero h1 span {
  background: var(--gradient-accent);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
}

.hero .lead {
  font-size: 1.1rem;
  color: var(--text-soft);
  margin-bottom: 26px;
  max-width: 560px;
  line-height: 1.8;
}

.hero-actions {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
}

/* 按钮 */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: var(--radius-pill);
  font-weight: 600;
  font-size: 0.95rem;
  transition: all var(--transition);
  border: 2px solid transparent;
  cursor: pointer;
  position: relative;
  overflow: hidden;
}

.btn-primary {
  background: var(--gradient-brand);
  color: #fff;
  box-shadow: 0 4px 16px rgba(26, 43, 76, 0.25);
}

.btn-primary:hover {
  background: var(--gradient-brand);
  color: #fff;
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(26, 43, 76, 0.35);
}

.btn-outline {
  border-color: var(--brand);
  color: var(--brand);
  background: transparent;
}

.btn-outline:hover {
  background: var(--brand);
  color: var(--bg);
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(26, 43, 76, 0.2);
}

/* 首屏统计 */
.hero-stats {
  display: flex;
  gap: 36px;
  margin-top: 36px;
}

.hero-stats > div {
  position: relative;
}

.hero-stats > div:not(:last-child)::after {
  content: "";
  position: absolute;
  right: -18px;
  top: 50%;
  transform: translateY(-50%);
  width: 1px;
  height: 36px;
  background: var(--border);
}

.hero-stats .stat-num {
  font-size: 1.8rem;
  font-weight: 800;
  color: var(--brand);
  line-height: 1.2;
  font-variant-numeric: tabular-nums;
}

.hero-stats .stat-label {
  font-size: 0.85rem;
  color: var(--text-soft);
}

/* ===== 轮播 ===== */
.carousel {
  position: relative;
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
  background: var(--bg-soft);
  aspect-ratio: 16 / 10;
  border: 1px solid var(--border);
}

.carousel-slide {
  position: absolute;
  inset: 0;
  opacity: 0;
  transition: opacity var(--transition-slow);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 30px;
}

.carousel-slide.active {
  opacity: 1;
  position: relative;
}

.carousel-slide svg {
  width: 100%;
  height: 100%;
  object-fit: cover;
  border-radius: 12px;
}

.carousel-nav {
  display: flex;
  gap: 8px;
  justify-content: center;
  margin-top: 16px;
}

.carousel-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--border);
  border: none;
  cursor: pointer;
  transition: all var(--transition);
  padding: 0;
}

.carousel-dot:hover {
  background: var(--text-muted);
}

.carousel-dot.active {
  background: var(--gradient-accent);
  width: 28px;
  border-radius: 10px;
}

/* ===== 通用区块 ===== */
section {
  padding: 70px 0;
}

.section-header {
  text-align: center;
  max-width: 720px;
  margin: 0 auto 48px;
}

.section-header h2 {
  font-size: 2rem;
  font-weight: 800;
  color: var(--brand);
  margin-bottom: 12px;
  letter-spacing: -0.02em;
  position: relative;
  display: inline-block;
}

.section-header h2::after {
  content: "";
  position: absolute;
  bottom: -8px;
  left: 50%;
  transform: translateX(-50%);
  width: 48px;
  height: 3px;
  background: var(--gradient-accent);
  border-radius: 3px;
}

.section-header p {
  color: var(--text-soft);
  font-size: 1.05rem;
  margin-top: 16px;
}

.bg-soft {
  background: var(--bg-soft);
}

/* ===== 卡片网格 ===== */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 24px;
}

.card {
  background: var(--gradient-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px 24px;
  transition: all var(--transition);
  box-shadow: var(--shadow-sm);
  position: relative;
  overflow: hidden;
}

.card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--gradient-accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition);
}

.card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg);
  border-color: var(--border-hover);
}

.card:hover::before {
  transform: scaleX(1);
}

.card h3 {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 10px;
  color: var(--brand);
}

.card p {
  font-size: 0.93rem;
  color: var(--text-soft);
  line-height: 1.8;
}

.card .icon {
  font-size: 1.8rem;
  margin-bottom: 14px;
  display: block;
  transition: transform var(--transition);
}

.card:hover .icon {
  transform: scale(1.15) rotate(-5deg);
}

/* ===== 文章列表 ===== */
.article-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 26px;
}

.article-card {
  background: var(--gradient-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  transition: all var(--transition);
  display: flex;
  flex-direction: column;
  box-shadow: var(--shadow-sm);
}

.article-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-5px);
  border-color: var(--border-hover);
}

.article-thumb {
  height: 160px;
  background: linear-gradient(135deg, var(--brand-light), var(--bg-soft));
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  position: relative;
}

.article-thumb::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, transparent 60%, rgba(0, 0, 0, 0.04));
}

.article-thumb svg {
  width: 100%;
  height: 100%;
  transition: transform var(--transition-slow);
}

.article-card:hover .article-thumb svg {
  transform: scale(1.06);
}

.article-body {
  padding: 20px;
  flex: 1;
  display: flex;
  flex-direction: column;
}

.article-meta {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 8px;
  display: flex;
  gap: 12px;
  align-items: center;
}

.article-meta time {
  font-variant-numeric: tabular-nums;
}

.article-meta span {
  padding: 2px 10px;
  background: var(--brand-light);
  border-radius: var(--radius-pill);
  color: var(--brand);
  font-weight: 500;
  font-size: 0.75rem;
}

.article-body h3 {
  font-size: 1.08rem;
  font-weight: 700;
  margin-bottom: 8px;
  line-height: 1.4;
}

.article-body h3 a {
  color: var(--brand);
  transition: color var(--transition-fast);
}

.article-body h3 a:hover {
  color: var(--brand-accent);
}

.article-body p {
  font-size: 0.9rem;
  color: var(--text-soft);
  flex: 1;
  line-height: 1.75;
}

.read-more {
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--brand-accent);
  margin-top: 12px;
  display: inline-flex;
  align-items: center;
  gap: 4px;
  transition: gap var(--transition-fast), color var(--transition-fast);
}

.read-more:hover {
  gap: 8px;
  color: var(--brand-accent-hover);
}

/* ===== FAQ ===== */
.faq-list {
  max-width: 840px;
  margin: 0 auto;
}

.faq-item {
  border-bottom: 1px solid var(--border);
  padding: 6px 0;
  transition: background var(--transition-fast);
}

.faq-item:last-child {
  border-bottom: none;
}

.faq-question {
  width: 100%;
  background: none;
  border: none;
  text-align: left;
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text);
  padding: 18px 0;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  font-family: inherit;
  transition: color var(--transition-fast), padding-left var(--transition-fast);
  line-height: 1.6;
}

.faq-question:hover {
  color: var(--brand);
  padding-left: 6px;
}

.faq-icon {
  font-size: 1.4rem;
  color: var(--brand-accent);
  transition: transform var(--transition);
  flex-shrink: 0;
  width: 28px;
  height: 28px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  background: var(--brand-light);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease, padding 0.3s ease;
  color: var(--text-soft);
  font-size: 0.95rem;
  line-height: 1.85;
}

.faq-item.open .faq-answer {
  max-height: 600px;
  padding-bottom: 18px;
}

.faq-item.open .faq-icon {
  transform: rotate(45deg);
  background: var(--brand-accent);
  color: #fff;
}

/* ===== HowTo ===== */
.howto-steps {
  display: grid;
  gap: 20px;
  max-width: 840px;
  margin: 0 auto;
}

.howto-step {
  display: flex;
  gap: 20px;
  background: var(--gradient-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  transition: all var(--transition);
  box-shadow: var(--shadow-sm);
}

.howto-step:hover {
  transform: translateX(6px);
  box-shadow: var(--shadow);
  border-color: var(--border-hover);
}

.step-num {
  flex-shrink: 0;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--gradient-brand);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 1.2rem;
  box-shadow: 0 4px 12px rgba(26, 43, 76, 0.25);
  transition: transform var(--transition);
}

.howto-step:hover .step-num {
  transform: scale(1.1) rotate(-8deg);
}

.howto-step h3 {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 6px;
  color: var(--brand);
}

.howto-step p {
  font-size: 0.92rem;
  color: var(--text-soft);
  line-height: 1.8;
}

/* ===== 团队 ===== */
.team-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 24px;
}

.team-card {
  text-align: center;
  background: var(--gradient-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px 20px;
  transition: all var(--transition);
  box-shadow: var(--shadow-sm);
}

.team-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg);
  border-color: var(--border-hover);
}

.team-card .avatar {
  width: 72px;
  height: 72px;
  border-radius: 50%;
  margin: 0 auto 14px;
  background: var(--brand-light);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.8rem;
  transition: transform var(--transition);
  border: 2px solid var(--border);
}

.team-card:hover .avatar {
  transform: scale(1.1);
  border-color: var(--brand-accent);
}

.team-card h3 {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--brand);
  margin-bottom: 6px;
}

.team-card p {
  font-size: 0.88rem;
  color: var(--text-soft);
  line-height: 1.7;
}

/* ===== 联系 ===== */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
  align-items: start;
}

.contact-info li {
  display: flex;
  gap: 12px;
  margin-bottom: 18px;
  font-size: 0.95rem;
  color: var(--text-soft);
  line-height: 1.7;
  transition: padding-left var(--transition-fast);
}

.contact-info li:hover {
  padding-left: 6px;
}

.contact-info .label {
  font-weight: 600;
  color: var(--text);
  min-width: 80px;
  flex-shrink: 0;
}

/* ===== 页脚 ===== */
.site-footer {
  background: var(--gradient-brand);
  color: #cbd5e1;
  padding: 56px 0 28px;
  font-size: 0.9rem;
  position: relative;
  overflow: hidden;
}

.site-footer::before {
  content: "";
  position: absolute;
  top: -80px;
  right: -80px;
  width: 280px;
  height: 280px;
  background: radial-gradient(circle, rgba(232, 93, 58, 0.12) 0%, transparent 70%);
  border-radius: 50%;
  pointer-events: none;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 36px;
  margin-bottom: 40px;
  position: relative;
  z-index: 1;
}

.footer-grid h4 {
  color: #fff;
  font-size: 1rem;
  margin-bottom: 16px;
  font-weight: 700;
  position: relative;
  padding-bottom: 8px;
}

.footer-grid h4::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 24px;
  height: 2px;
  background: var(--brand-accent);
  border-radius: 2px;
}

.footer-grid ul li {
  margin-bottom: 10px;
}

.footer-grid a {
  color: #a8b8d0;
  transition: color var(--transition-fast), padding-left var(--transition-fast);
  display: inline-block;
}

.footer-grid a:hover {
  color: #fff;
  padding-left: 4px;
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.12);
  padding-top: 24px;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 14px;
  font-size: 0.82rem;
  color: #8fa2c0;
  position: relative;
  z-index: 1;
}

.footer-bottom a {
  color: #a8b8d0;
}

.footer-bottom a:hover {
  color: #fff;
}

/* ===== 返回顶部 ===== */
.back-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--gradient-brand);
  color: #fff;
  border: none;
  cursor: pointer;
  font-size: 1.3rem;
  box-shadow: var(--shadow-lg);
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition);
  z-index: 900;
  display: flex;
  align-items: center;
  justify-content: center;
}

.back-top.show {
  opacity: 1;
  visibility: visible;
}

.back-top:hover {
  transform: translateY(-4px) scale(1.08);
  box-shadow: var(--shadow-glow);
  background: var(--gradient-accent);
}

/* ===== 滚动动画 ===== */
.fade-up {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-up.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ===== 暗色模式特殊处理 ===== */
body.dark .site-header {
  background: var(--glass-bg);
}

body.dark .hero {
  background: var(--gradient-hero);
}

body.dark .card,
body.dark .article-card,
body.dark .team-card,
body.dark .howto-step {
  background: var(--gradient-card);
}

body.dark .logo svg {
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.4);
}

body.dark .btn-primary {
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.4);
}

body.dark .btn-primary:hover {
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.5);
}

body.dark .step-num {
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.4);
}

body.dark .article-thumb {
  background: linear-gradient(135deg, var(--brand-light), var(--bg-soft));
}

body.dark .site-footer {
  background: linear-gradient(135deg, #0a1526 0%, #111a2e 100%);
}

/* ===== 响应式 ===== */
@media (max-width: 1024px) {
  .hero h1 {
    font-size: 2.4rem;
  }

  .footer-grid {
    grid-template-columns: 1.5fr 1fr 1fr;
  }
}

@media (max-width: 900px) {
  .hero-grid {
    grid-template-columns: 1fr;
    gap: 36px;
  }

  .hero h1 {
    font-size: 2.1rem;
  }

  .nav-links {
    display: none;
  }

  .menu-toggle {
    display: block;
  }

  .search-box {
    display: none;
  }

  .contact-grid {
    grid-template-columns: 1fr;
  }

  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }

  .hero-stats {
    gap: 28px;
  }

  .hero-stats > div:not(:last-child)::after {
    right: -14px;
  }
}

@media (max-width: 600px) {
  body {
    font-size: 15px;
  }

  .hero {
    padding: 40px 0 36px;
  }

  .hero h1 {
    font-size: 1.7rem;
  }

  .hero .lead {
    font-size: 1rem;
  }

  .hero-actions {
    flex-direction: column;
  }

  .hero-actions .btn {
    width: 100%;
    justify-content: center;
  }

  .hero-stats {
    flex-wrap: wrap;
    gap: 20px 28px;
  }

  .hero-stats > div:not(:last-child)::after {
    display: none;
  }

  .hero-stats .stat-num {
    font-size: 1.5rem;
  }

  .section-header h2 {
    font-size: 1.5rem;
  }

  .section-header p {
    font-size: 0.95rem;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 28px;
  }

  .howto-step {
    flex-direction: column;
    gap: 14px;
  }

  .step-num {
    width: 40px;
    height: 40px;
    font-size: 1rem;
  }

  section {
    padding: 48px 0;
  }

  .card {
    padding: 22px 20px;
  }

  .article-grid {
    grid-template-columns: 1fr;
  }

  .back-top {
    bottom: 20px;
    right: 20px;
    width: 42px;
    height: 42px;
    font-size: 1.1rem;
  }

  .contact-info li {
    flex-direction: column;
    gap: 4px;
  }

  .contact-info .label {
    min-width: auto;
  }

  .footer-bottom {
    flex-direction: column;
    text-align: center;
  }
}

@media (max-width: 400px) {
  .hero h1 {
    font-size: 1.5rem;
  }

  .section-header h2 {
    font-size: 1.3rem;
  }

  .logo {
    font-size: 1.15rem;
  }

  .logo svg {
    width: 30px;
    height: 30px;
  }
}

/* ===== 打印样式 ===== */
@media print {
  .site-header,
  .mobile-menu,
  .back-top,
  .carousel-nav,
  .theme-toggle,
  .menu-toggle,
  .search-box {
    display: none !important;
  }

  body {
    padding-top: 0;
    color: #000;
    background: #fff;
  }

  .card,
  .article-card,
  .team-card,
  .howto-step {
    box-shadow: none;
    border: 1px solid #ccc;
    break-inside: avoid;
  }
}

/* ===== 减少动画偏好 ===== */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }

  .fade-up {
    opacity: 1;
    transform: none;
  }
}

/* ===== 高对比度模式 ===== */
@media (prefers-contrast: high) {
  :root {
    --border: #000;
    --text-soft: #000;
  }

  body.dark {
    --border: #fff;
    --text-soft: #fff;
  }
}

/* ===== 焦点可见性 ===== */
:focus-visible {
  outline: 2px solid var(--brand-accent);
  outline-offset: 2px;
  border-radius: 4px;
}

button:focus-visible,
a:focus-visible,
input:focus-visible {
  outline: 2px solid var(--brand-accent);
  outline-offset: 2px;
}
```